56413-47-9Relevant articles and documents
A rare μ-hydroxo-bridged species. Synthesis, structure, and properties of μ-hydroxo(tetraphenylporphyrinatomanganese(III))(phthalocyaninato-(azido) chromium(III)), [(TPP)Mn-O(H)-CrPc(N3)]
Donzello, Maria Pia,Bartolino, Laura,Ercolani, Claudio,Rizzoli, Corrado
, p. 6988 - 6995 (2008/10/09)
A novel ditetrapyrrolic, heteroleptic, and heterometallic (Mn-Cr) μ-hydroxo-bridged complex has been prepared, and its structural and general properties have been studied. The species μ-hydroxo(tetraphenylporphyrin- atomanganese(III))(phthalocyaninato(azido)chromium(III)), [(TPP)Mn-O(H)- CrPc(N3)], isolated as a chloronaphthalene (CINP) solvate, has been structurally characterized by single-crystal X-ray work. The two (TPP)Mn and CrPc(N3) fragments are held together by the bridging μ-hydroxo ion with long Mn-O [1.993(5) A] and Cr-O [1.976(5) A] bond distances and a Mn-O(H)-Cr angle of 163.7(3)°. The five-coordinate Mn center in the (TPP)Mn fragment is displaced from the TPP rigorously planar central N 4 core by 0.128 A, and the environment is typical of a Mn III high-spin site. The six-coordinate CrIII in the CrPc(N3) moiety lies practically in the plane of the phthalocyanine macrocycle (displacement toward the azido group: 0.054 A). The average Mn-Npyr and Cr-Npyr bond distances are 2.011(6) and 1.982(6) A, respectively, and the Mn-Cr bond distance is 3.929(2) A. The porphyrin and phthalocyanine rings are in an almost eclipsed position [5.16(2)°], and the mean planes of the two macrocycles form a dihedral angle of 5.79(4)°. Crystal data for [(TPP)Mn-O(H)-CrPc(N3)] ·2CINP, C76H45CrMnN15O·2C 10H7Cl: a = 16.645(3) A, b = 17.692(4) A, c = 25.828(5) A, α = 90°, β= 98.79(3)°, γ= 90°, space group P21/c (No. 14), V = 7517(3) A3, Z= 4, R1 = 0.086, and wR2 = 0.267. IR-and UV-vis-near-IR spectral and room temperature magnetic susceptibility data of the [Mn-Cr] species are also presented.
Study of (Tetraphenylporphinato)manganese(III)-Catalyzed Epoxidation and Demethylation Using p-Cyano-N,N-dimethylaniline N-Oxide as Oxygen Donor in a Homogeneous System. Kinetics, Radiochemical Ligation Studies, and Reaction Mechanism for a Model of Cytochrome P-450
Powell, Michael F.,Pai, Emil F.,Bruice, Thomas C.
, p. 3277 - 3285 (2007/10/02)
Oxygen transfer from p-cyanodimethylaniline (p-CNDMANO) to cyclohexene as well as "intramolecular" oxygen transfer accompained by demethylation to yield p-cyanomonomethylaniline (p-CNMMA) are strongly catalyzed by ligated (tetraphenylporphinato)MnIII (i.e., XMnIIITPP).These reactions have been studied in dry, oxygen-free benzonitrile.Radiochemical studies show that H2O (or TOH) is not bound to XMnIIITPP in aprotic solvents so that the MnIII moiety is pentacoordinate.Oxygen transfer occurs through the reversible formation of the hexacoordinated species p-CNDMANO*MnIII(X)TPP.This species decomposes to p-cyanodimethylaniline (p-CNDMA) + O=MnV(X)TPP.Reactions of cyclohexene with O=MnV(X)TPP yields cyclohexene epoxide and XMnIIITPP whereas p-CNMMA is formed directly from the p-CNDMANO*MnIII(X)TPP complex.The rates of product formation are shown to be dependent upon the nature of the ligand (X- = F-, Cl-, Br-, I-, OCN-).In the absence of the axial ligand X-, the rates of reaction are extremely slow.Thus, the MnIII C2-cap-porphyrin (XMnIIICAPTPP), which can only form an O=MnV porphyrin species wherein the Mn moiety is not complexed to X- as a sixth ligand, shows almost no tendency to act as a catalyst for oxygen transfer.The necessary presence of the axial ligand X- and the dependence of rate upon X- requires the structure of the oxygen transfer species to be quivalent to O=MnV(X)TPP.A kinetic analysis is presented (Scheme III) which has allowed the determination of the influence of the ligands X- upon the various rate constants (Table IV) involved in the overall oxidations.By employing p-CNDMANO as oxygen donor, multiple catalytic turnovers without loss of porphyrin have been realized.
